A novel microarray-based system is proposed for diagnosis of tuberculosis and tuberculosis-like respiratory infections. This diagnostic system offers a parallel method to screen clinical samples for the presence of DNA sequences from Mycobacterium tuberculosis, the causative agent of human tuberculosis, and closely related mycobacterial species, while simultaneously screening specimens for more distantly related mycobacteria and other common infectious agents known to cause tuberculosis-like symptoms. The system selectively amplifies targeted DNA sequences using repeated rounds of primer-directed extension. Unlike the PCR, this method generates short extension products whose lengths are limited by using one of the building blocks in a form that terminates the extension reaction when it is incorporated. Restricting the extension reaction to the production of short extension products allows screening for many pathogens with a single reaction. The technique is very selective because a signal is produced only when the extension reaction products hybridize to probes immobilized on the microarray. This requires that: 1), the primer binds with a complementary sequence on the targeted DNA, and 2) the resulting short extension sequence is complementary to the probe on the microarray used to detect the extension product. Both of these are very selective processes.